Using the log you uploaded (no signup required, b*cat), I have attached a montage for your connection, covering the last 6 days.
As SNRM is of most concern, I have also attached a higher resolution image of combined DS/US SNRM for the same period that can be zoomed in to in order to see finer details.
We can now see a general pattern for the timing of the issue, with the increases in error counts being the result of the reduced SNR/SNRM.
From memory, NewtonStar had/has a similar issue during the evenings.
His QLN graph indicates the frequencies being affected are those used by Radio China (or some other radio station(s).
This is not particularly unusual overnight, as you may/may not have noticed when scrolling through Medium Wave/AM radio stations during hours of darkness.
A lot of foreign stations can be clearly heard that are simply not heard during daylight hours.
Whereabouts are you located?
Someone else may be able to suggest which radio stations might be having this effect upon your connection.
My own connection doesn't appear to be too affected by this phenomenon, but I can clearly hear a Spanish radio station from around 20:00 each night.
I do also have some slight concerns regarding the appearance of your Hlog graphs that you have posted previously.
There is SOME indication of a possible HR issue at the higher frequencies that you connection can use.
There may be some mileage in rebooting the modem at around 22:00 or 23:00 one night (when SNRM generally seems to be at its worst), just to see what difference it makes to your QLN graph.
Doing this would no doubt result in lower sync speeds, so another reboot during daylight hours may restore the sync speed, but re-introduce increased error counts during the evenings.
What I have mentioned above could all be a red herring, but if not, it appears you would be unable to do much about it.
